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In a world driven by the Internet and the readily accessible information it provides, there exists a high demand to easily discover and collect vast amounts of data available over several scientific domains and numerous data types. To add to the complexity, data is not only available through a plethora of data sources within disparate systems but also represents differing scales of space and time. One clear divide that exists in the world of information science and technology is the disjoint relationship between hydrologic and atmospheric science information. These worlds have long been split between observed time series at discrete geographical features in hydrologic science and modeled or remotely sensed coverages or grids over continuous space and time domains in atmospheric science. As more information becomes widely available through the Web, data are being served and published as Web services using standardized implementations and encodings. This paper illustrates a framework that utilizes Sensor Observation Services, Web Feature Services, Web Coverage Services, Catalog Services for the Web and GI-cat Services to index and discover data offered through different classes of information. This services infrastructure supports multiple servers of time series and gridded information, which can be searched through multiple portals, using a common set of time, space and concept query filters. [ABSTRACT FROM AUTHOR]

For Digital Earth, an important priority is to integrate data from multiple sources. Interoperability and metadata are key instruments to reach such an objective. Interoperability is achieved by adopting and applying international standards for service interfaces and data models. As far as geospatial information is concerned, interoperability recognizes three important, interrelated data concepts: feature, coverage, and map. The present work deals with Web services for coverage access. Coverage perspectives characterizing three geospatial communities - i.e. the Earth Science (ES), GIS and Digital Earth communities, are discussed. ES community requirements for coverage access services are presented and discussed making use of two methods concurrently: Critical Success Factor (CSF) analysis method supplemented through the use of Usage Cases. A CSF hierarchy and derived critical requirements and problems are introduced. An implementation approach consisting of four general principles is proposed. Access service categories emerging from the analysis are presented and their comparison with the present access services for the ES is discussed. [ABSTRACT FROM AUTHOR]

As far as interoperability is concerned, in a service-oriented framework, it is possible to distinguish different service tiers; each tier contains systems and tools which implement that tier's specific task. The present paper analyses such a framework for the Earth Sciences and the GIS information communities. For the Earth Sciences community, the heterogeneity of existing protocols and data models is outlined, considering the experience of the Unidata community. For the GIS community, the interoperability opportunities laid by the OGC's specifications are briefly introduced. The need of achieving the two communities' frameworks interoperability, and its importance for science Digital Library applications are introduced. A solution is presented and discussed; it is based on the following technologies: THREDDS Data Server, OGC WCS/WFS and ncMLGML. An OGC interoperability experiment, which tests the proposed solution, is briefly presented. [ABSTRACT FROM AUTHOR]